Field of the Invention
The present disclosure relates to a method for producing a carboxylic acid anhydride, a method for producing a carboxylic imide, and a method for manufacturing an electrophotographic photosensitive member.
Description of the Related Art
Carboxylic acid anhydrides such as dicarboxylic acid monoanhydrides and tetracarboxylic acid dianhydrides are widely used as a material for organic electronic devices such as electrophotographic photosensitive members, photoelectric conversion elements, and organic electric field light-emitting elements, and as a raw material or an intermediate of polyimide resins.
For example, Japanese Patent Laid-Open No. 2014-29479 discloses an electrophotographic photosensitive member used in a process cartridge or an electrophotographic apparatus, and in this disclosure, tetracarboxylic diimide produced by a reaction of a tetracarboxylic acid anhydride and an amine is used as an electron transporting material.
There have been devised processes for producing a carboxylic acid anhydride by heating a solid dicarboxylic or tetracarboxylic acid or by heating a dicarboxylic or tetracarboxylic acid in acetic anhydride. Japanese Patent Laid-Open No. 62-59280 discloses a method for dehydrating pyromellitic acid by indirectly heating pyromellitic acid with a heat medium having a temperature of 240° C. or more. Japanese Patent Laid-Open No. 1-50876 discloses a method for dehydrating biphenyltetracarboxylic acid by heating biphenyltetracarboxylic acid at 250° C. or more.